PREPARATION AND EVALUATION OF POLYURETHANE FOAM RUBBER MEMBRANE-BASEDSAMPLERS FOR USE IN ISOCYANATE SAMPLING/

In order to collect isocyanate in both aerosol and vapor forms, we hav e developed a dual-membrane sampler which features a moist porous bed, backed up by an impermeable membrane. A polyester-polyurethane foam ( PUF) was selected to function as the porous bed, and it was evaluated for its ability to resist solvent degradation and swelling while permi tting rapid air penetration. Natural rubber (NR) and styrene-butadienc e rubber (SBR) membranes were prepared to serve as backup membranes. T hese were also evaluated for their solvent compatibility and air-penet ration characteristics. A polyester-polyurethane foam backed up by a N R membrane prepared by an efficient vulcanization procedure was select ed as the best combination for development of the isocyanate sampler. Recovery studies Lasing the hexamethylene-based polyisocyanate, biuret , indicate better than 80% recovery of polyisocyanate after applicatio n to the PUF.